whitehatspecial:
I have a 340 engine which was recently (within 8 months) rebuilt using a hydraulic Comp Cams cam and lifters. I used a local engine builder and had the orig iron 340 heads redone. installed new adjustable Mopar ductile rockers, shafts, and cupped pushrods.

I've had tuning problems (running rich) and clacking on startup. Tonight I decided to pull the valve covers to check the valve adjustments. Sure enough many rockers where adjusted very loosely. I re-adjusted them using the " adjust exhaust valve when the intake opens, etc." method. Some pushrods seemed to stop spinning almost immediately when I turned the adjuster in and others seemed to tighten up more gradually.

When I was through the car was quieter but I noticed that several (about 5) of the adjustable rockers have much less threaded part showing (about a 1/4" of thread vs. 1/2" on the rest. Does this mean those lifters are collapsed or failed? How can you tell if the lifters are bad? Thanks.

aifilaw:
lifter problems can be diagnosed in one of three ways usually...1. measure lift at the pushrod while turning the crank/cam and check against the sheet2. press down with your hand on a lifter that was just run with the valve covers off (shouldn't budge, if it does, then its failing)3. pull it out and look at the bottom

two main lifter failures I've seen in the last 3 years are they won't maintain pressure, and the metal is the same hardness as the cam (poor manufacturing), so I could either push down on them with my hand immediately after running the engine, or I pulled them out and the center was worn in a concave form.

aifilaw:
honestly, the last time I really looked at this situation was when I realized that two of the main lifter companies had gone out of business and it left 1, maybe 2 still in place.... one of those had the market and decided to take advantage of it with poor quality control....now when I say manufacturing company, I mean everybody...as an example when you buy a Pioneer, a Sony, a Toshiba DVD player...your getting the same exact internal hardware, different cover plates and exterior, and different firmware (code)...most people don't know this.

The same is true with a lot of things, so crane, summit, et cetera were all getting their lifters from the same place, and slapping their name brand on them....as I recall in the worst part of this a few years ago people were averaging about 1-2 out of 16 lifters were total crap within breakin, and 2-3 more would fail within the first 1,000 miles...usually ended up in engines needing to be taken back apart...I assume the problems have been sorted out, but I can't tell you where to go for lifters...someone else will need to chime in who has had recent experience with them